Process for dyeing polypropylene blends



United States Patent 7 Claims. (c1.s 21

The present invention concerns a new process for dyeing shaped materials based upon blends of crystalline polypropylene (which will hereinafter be referred to simply as polypropylene) and polyamides, the term including both isopolyamides and interpolyamides. These blends, which are hereinafter referred to simply as polypropylene blends, may be of very diverse character and include, in particular, blends consisting of 95- 85% of polypropylene and 15'% of an interpolyamide obtained by polycondensation of 30-50 parts per hundred of hexarnethylenediamine adipate and 70-50 parts per hundred of hexamethylenediamide sebacate.

The dyeing of polypropylene blends, while easier than that of pure polypropylenes, is practicable only with a limited number of classes of dyes and generally necessitates dyeing at very high temperature, sometimes under pressure. Even using such drastic conditions it is not possible to obtain dark and vivid shades.

It is an object of the present invention to provide a new process for colouring (by dyeing or printing) materials consisting of polypropylene blends, by means of which it is possible to obtain readily on these materials even dark shades.

According to the present invention there is provided a process for dyeing materials made of polypropylene blends as herein defined which comprises dyeing the materials at a temperature above 95 C. and in the presence of orthophenylphenol and a cyclic hydrocarbon or chlorinated cyclic hydrocarbon which is a non-solvent for the said materials under the conditions of said treatment, the weight ration of orthophenylphenol to the said hydrocarbon being between 5:1 and 2:1.

The dyeing may be effected from a dye bath or by means of a printing paste or by other methods known per se.

Orthophenylphenol can be used in the free state or in the form of a salt. When orthophenylphenol is used in the free state, it is preferably used in emulsified form. The quantity of orthophenylphenol to be added to a dyeing bath may vary between 1 and g./l., but it is generally advantageous to maintain it between 3 and 6 g./|l.

It is essential that the cyclic hydrocarbon or cyclic chlorinated hydrocarbon to be added to the dyeing bath or to a printing paste should be compatible with orthophenylphenol both at ambient temperatures and at the temperatures necessary for carrying out the process. As particularly suitable cyclic hydrocarbons and chlorinated cyclic hydrocarbons there may be mentioned, inter alia, the following: Xylene, decahydronaphthalene, tetrahydronaphthalene, orthod-ichlorobenzene and trichlorohenzene.

For use, the cyclic hydrocarbon or chlorinated cyclic hydrocarbon is emulsified, preferably with water and an appropriately chosen surface-active agent, for example a product of condensation of ethylene oxide with a fatty alcohol. The process according to the invention is easy to apply because the dyeing mixtures as defined readily wet the materials to be dyed, despite the hydrophobic character of the latter. Thus, a filament of polypropylene/interpolyamide blend placed in a bath containing no cyclic hydrocarbon is wetted only after 40 minutes, while in a bath containing 1 cc. of decahydronaphtha- 3,199,940 Patented Aug. 10, 1965 lene per litre the time taken for the wetting of the same material is reduced to 8 seconds.

The weight ratio of orthophenylphenol to hydrocarbon is between 5:1 and 2:1 and most advantageously is 3:1. The weight ratio of the dyest-ulf to the non-solvent may vary from 6:1 to .12: 1, preferably 1.2:1 to .6: 1.

The temperature, while remaining above C., may vary in accordance with the class of dyes employed, but will generally bebetween 95 and C.

The orthophenylphenol and the cyclic hydrocarbon or chlorinated cyclic hydrocanbon may be added separately to the dyeing bath or to the printing paste. Alternatively, they may be previously mixed and dispersed in water, and this mixture may be added to the dyeing bath or to the printing paste.

It is possible by the process according to the invention to dye at boiling point and thus to avoid dyeing under pressure and at excessively high temperatures.

The process according to the invention may be applied to the colouring of any shaped materials consisting of polypropylene blends, such as yarns, fibres, filaments, tows, cables, woven articles, knitted articles and films. In contradistinction to the previously known processes, it can be employed to produce dark and vivid shades without exceeding 100 C. during the dyeing treatment. It also permits a much wider choice of dyes, such as plastosoluble dyes, basic dyes, vat dyes, reactive dyes and in particular acid dyes and metalliferous dyes, with which it is possible to obtain very fast dark shades which have higher resistance to scouring solvents.

The following example, in which the parts and percentages are by weight, will serve to illustrate the invention.

Example A dyeing bath having the following composition is prepared:

Part-s Water 1000 An anthraquinone dye sold by Du Pont under'the trade name Latyl Blue FL 0.6 Sodium orthophenylphenate 3.0 'I riclrlorobenzene 1 .0 Diarnmonium phosphate 5.0

l 1 IH-@ omomou (American Dyestuif Reporter, July 5, 1954).

I claim:

1. A process for dyeing a material consisting essentially of a blend of crystalline polypropylene and a polyamide, which comprises dyeing the material at a temperature above 95 C. and in the presence of orthophenylphenol and a compound which is a non-solvent for the said blend under the treatment conditions and is selected from the class consisting of liquid monocyclic or bicyclic hydrocarbons and their chlorination products, the weight ratio of the orthophenylphenol and the said non-solvent compound being between the limits 5:1 to 2:1, and the weight ratio of dye material to said non-solvent compound is between ratio of the orthophenylphenol and the said non-solvent compound being between the limits 5:1 to 2:1, and the weight ratio of dye material to said non-solvent compound is between 6:1 and 0.12:1.

3. A process for dyeing a material consisting essentially of a blend of crystalline polypropylene and an interpolyamide derived from -50 parts per 100 of hexamethylenediamine adipate and -50 parts per 100 of hexamethylenediamine sebacate, which comprises dyeing the material at a temperature above C. and in the presence of orthophenylphenol and a compound which is a nonsolvent for the said blend under the treatment conditions and is selected from the class consisting of liquid monocyclic or bicyclic hydrocarbons and their chlorination products, the weight ratio of the orthophenylphenol and the said non-solvent compound being betweenthe limits 5:1 and 2:1, and the weight ratio of the dye material to said non-solvent compound is between 12:1 and 0.6:1.

4. A process for dyeing a material consisting essentially of a blend of or stallineol ro lene and a 01 amide 1 1 y p yp W p y substantlally 3:1, and the weight ratio of the dye matewhich comprises dyeing the material at 95 to C. and in the presence of orthophenylphenol and a compound which is a non-solvent for the said blend under the treatment conditions and is selected from the class consisting of liquid monocyclic or bicyclic hydrocarbons, and their chlorinataion products, the Weight ratio of the orthophenylphenol and the said non-solvent compound being between the limits 5:1 and 2: l, and the weight ratio of the dye material to said non-solvent compound is between 1.2:1 and 0.621.,

5. A process for dyeing a material consisting essentially ofa blend of crystalline polypropylene and a polyamide which'comprises dyeing the material by treatment with a yebath at a temperature above 95 C. and in the presence of 1 to 10 grams per litre of dyebath of orthophenylphenol and a compound which is a non-solvent for the said blend under the treatment conditions and is selected from the class consisting of liquid monocyclic or bicyclic hydrocarbons and their chlorination products, the weight ratio of the orthophenylphenol and the said non-solvent compound being between the limits 5:1 to 2:1, and the weight ratio of the dye material to said non-solvent compound is between 1.2:1 and 06:1.

6. A process for dyeing a material consisting. essentially of' a blend of crystalline polypropylene and an interpolyamide which comprises dyeing the material by treatment with a dyebath at a temperature above 95 C. and in the presence of 3 to 6 grams per litre of dyebath of orthophenylphenol and a compound which is a non-solvent for the said blend under the treatment conditions and is selected from the class consisting of liquid monocyclic or bicyclic hydrocarbons and their chlorination products, the weight ratio of the orthophenylphenol and the. said non-solvent compound'being between the limits 5:1 to 2:1, and the weight ratio'of the dye material to said non-solvent compound is between 12:1 and 0.6:1.

'7. A process for dyeing a material consisting essentially of a blend of crystalline polypropylene with an interpolyamide derived from '3050 parts per 100 of 'hexamethylenediamine adipate and 70-50 parts per 100 of hexamethylenediamine sebacate, which comprises dyeing the material by treatment in a dyebath at 95 to 100 C. containing 3 to 6 grams per litre of orthophenylphenol and containing ;a compound which is a non-solvent for the said blendunder the treatment conditions and is selected from the class consisting of liquid monocyclic or bicyclic hydrocarbons, and their chlorination products, the weight ratio of orthophenylphenol to the said compound being rial to said non-solvent compound is between 12:1 and 0.6:1.

References Cited by the Examiner UNITED STATES PATENTS 2,869,969 l/59 Schulze 8-21 X 3,023,072 2/62 Dabrowski.

' FOREIGN PATENTS" 445,345 3/36 Great Britaiin v 809,495 2/ 59 Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

MORRIS O. WOLK, Examiner. 

1. A PROCESS FOR DYING A MATERIAL CONSISTING ESSENTIALLY OF A BLEND OF CRYSTALLINE POLYPROPYLENE AND A POLYAMIDE, WHICH COMPRISES DYEING THE MATERIAL AT A TEMPERATURE ABOVE 95*C. AND IN THE PRESENCE OF ORTHOPHENYLPHENOL AND A COMPOUND WHICH IS A NON-SOLVENT FOR THE SAID BLEND UNDER THE TREATMENT CONDITIONS AND IS SELECTED FROM THE CLASS CONSISTING OF LIQUID MONOCYCLIC OR BICYCLIC HYDROCARBONS AND THEIR CHLORINATION PRODUCTS, THE WEIGHT RATIO OF THE ORTHOPHENYLPHENOL AND THE SAID NON-SOLVENT COMPOUND BEING BETWEEN THE LIMITS 5:1 TO 2:1, AND THE WEIGHT RATIO OF DYE MATERIAL TO SAID NON-SOLVENT COMPOUND IS BETWEEN 6:1 AND 0.12:1. 